Refrigeration



May 1931.

' B. K. G. EHNBOM REFRIGERATION 2 sheets r-sheet 1 Original Filed Oct. 15, 1928 mm x 30 INVEN'ZCZ; BY m y 1931- B. K. G. EHNBOM 1,805,656

REFRIGERATION ori in-a1 Filed Oct. 15, 1928 2 Sheets-Sheet 2 Patented May 19, 1931 UNITED stares PATENT V-QOFFICE,

BO KARL GEORGE EHlWBOMI, OF STOCKHOLM, SWEDEN, ASSIG-NOR TO ELEGTROLUX SERVEL CORPORATION, OF NEW YORK, N. Y., A. GORPORATION OF DELAWARE nnrnrennnrron Application filed October 15, 1928, Serial No. 312,624, and in Germany January 6, 1928. Beneuied September 29, 1930.

My invention relates to refrigerating apparatus and particularly to types of apparatus including parts wherein there is gas and liquid contact over extended'surfaces.

In one phase of my invention it relates to refrigerating apparatus of the absorption typegiven size of parts. I aimto provide a large surface for gas and liquid contact within a small volume occupied by the arts of the apparatus in which the'gas an liquid contact takes place while at the same time providing effective heat transfer.

In applying the invention to refrigerating apparatus wherein series of plates are used on which liquid is held, I'pr'ov de means on the under-sides of such plates for retaining a film, preferably a'capillary film, of liquid adjacent the plates; The means for providing the capillary film on the under-sides of the ,plates ispreferably metallic in order to provide good heat transfer between theinside and outside of the vessel in which the plates are placed. While various means of accomplishing the result are possible I prefer to eme p 'clined to the horizontal, upwardly to rect1- ploy metallic wire screening held underneath such plates and adjacent thereto and'so ar- 5 ranged as to contact liquid placed on the upper-sides of the plates so that the liquid may be driven by capillary attraction to the under-sides of the plates. v V V The invention will be described more in detail with reference to the accompanying drawings showing several forms of apparatus embodying the invention and applied to a Fig. shows one type of plate which may be used in the absorber or evaporator of Fig. 1, tlBl ls. tylpe being diagrammatically indicated in 1g. v

Fig. 3 is atop new of the plate shown in Fig. 2;

.Figs. 4 and 5 show a cross-sectional and a I flue 14 extends centrally through both auxili'ary generator 12 and the main generator 11. A suitable source of heat, as for example the gas burner 15, is located below, and may extend upwardly within, flue 14. .A thermosiphpn or percolator conduit'16 establishes communication between auxiliary generator 12 and main generator 11. The lower end of conduit 16 extends for some distance within auxiliary generator 12. The portion of conduit 16 within auxiliary generator '12 is provided with one or more capillary ports 17.

A conduit 18 communicates with'the upper art of main generator 11 and extends, in-

fier 20. Rectifier .20 comprises a U-shaped member 21 around one branch of which is a member 22 to which conduit 18 is connected. Connected to the upper part of member 22 is a condenser tube 23 which passes in heat exchange relation with a cooling water conduit 24 and is connected to the right-handbranch 'of U-shaped member 21, asshown. The branch of the U-shaped member 21 whichis within jacket member 22 is open at the top so that it communicates with condenser tube 23. This branch is surrounded by bafiies 25 within member 22.

A conduit 26 is-connected to the lower part of the rectifier, extends downwardly within conduit 27, horizontally through heat exchanger 28, upwardly through conduit 29 and terminates in a bend30 which extends into an evaporator 31 situated within the space to be cooled. A conduit 32 connects the lower part of evaporator 31, with heat exchanger 28. The heat exchanger comprises a head 33 and a head 34 forming end chambers 35 and 36. These end chambers are connected by tubes 37 A space 38 is formed between heads 33 and 34Pand outside tubes 26 and 37 To this space 38 conduit 32 is connected. Aconduit 39 connects the lowerpart of space 38 with the lower part'of an absorber 40. Conduit 27 connects the upper part of absorber 40 with chamber 35.

A conduit 42 connects the lower part of absorber 40 with the upper part of auxiliary generator 12. A conduit 43 connects the lower part of main generator 11 with the upper part of absorber 10. These conduits are in'heat exchange relation as indicated at 4A.

Heads 33 and 34 are provided with apertures to permit entrained liquid in spaces 35 and 36 to drain into space 38 and thence to the absorber. A vent pipe 47 connects the rectifier with space 38. The absorber is cooled by a cooling water coil 48 which is connected with conduit 24.

Evaporator 31 and absorber 40 contain plates 50 the nature of which will be presently explained.

In operation: Heat applied to. the main generator 11 drives the cooling agent or refrigerant out of solution- I shall refer toammonia as the cooling agent and water as the absorption liquid, but without limitation. The apparatus shown being of the equalized pressure type also contains an auxiliary agent for which fluid I prefer hydrogen. Ammonia vapor driven out of solution in'the generator passes through conduit 18 to rectifier 20, carrying along some entrained water or steam or both. The vapor of absorption liquid thus entrained is separated out from the ammonia vapor in the rectifier and caused to return toward the generator through conduit 18. The cooling to effect the separation of absorption liquid is obtained due to the presence of liquid ammonia in the U-shaped member 21 which has been condensed in condenser tube 23. Ammonia vapor passes into conduit 23 from both member 22 outside the U-shaped member and from above the surface of liquid in that part of the U-shaped member which is within jacket 22.

Liquid ammonia passes through conduit 26 and into evaporator 31 where it flows over the plates 50. Hydrogen is admitted to the evaporator through conduit 29. The ammonia diffuses into the hydrogen and evaporates thus taking up heat from the surround- 4 ings and producing refrigeration. A mixture of hydrogen and ammonia gas is formed which passes downwardly through conduit 32 and through space 38 and conduit 39 into the lower part of absorber 40. In the absorber 40 weak absorption liquid separates ammonia from the hydrogen and the liberated hydrogen passes through conduit 27, space 35, tubes 37 space 36 and conduit 29 into the evaporator. Circulation of the hydrogen is produced between the evaporator and absorber due to the difference in specific weight of a mixture of ammonia gas and hydrogen on the one hand and hydrogen alone on the other hand.

Strong absorption liquid flows through conduit 42 and is lifted through thermosiphon tube 16 due to the heat applied to auxiliary generator 12 and the formation of vapor therein. The weak absorption liquid from which ammonia has been expelled passes throu h conduit43 into the upper part of absor r 40 and flows over the plates 50 in the absorber. Circulation between the absorber and generator is produced by the lifting efi'ect of auxiliary generator 12 and thermo-siphon tube 16.

In apparatus of the general type above described it previously has been common to use plates in the absorber and evaporator structure to maintain pools of liquid on the upper surfaces thereof. Raised rims around apertures in the plates have been used to maintain pools of liquid on these plates. Such plates are shown in U. S. Patent No. 1,609,334

granted December 7,1926. These plates are not designed to use the under-sides for gas and liquid contact. It has been proposed to use a fibrous material underneath plates of this nature for holding liquid but such fibrous material is not permanent, is not readily secured in place and does not afford the neces sary conduction of heat. I provide a wire mesh screen 51 having a great number of wires per square inch. I

In the arrangement shown in Figs. 2 and 3 the plate 50 is made circular to fit the preferably circular form of the vessel iii which it is contained with a segment cut-away to provide for flow of liquid downwardlylfrom one plate to another. The underside of the late carries the wire mesh 51 which is to ded around the segment edge of the plate so as to be in contact with liquid on the upper surface. While the side edge of one plate can serve to hold the wire mesh to the nextadjacent higher plate, I prefer to secure the wire mesh to the plate by spot-welding or soldering the wire mesh in places to the plate. This further 1 provides good heat conductivity. The wire mesh holds a capillary film on the under-side of plate 50. Liquid is drawn by capillary attraction around the segment edge and to the under-side.

In the evaporator the liquid ammonia evaporates and conducts heat into'the evaporator from the surroundings. In the absorber heat is expelled from the absorber into the surrounding cooling water coil. It will be obvious that the metal wire mesh provides good conductivity while at the same time holding the capillary film adjacent the metal plate so as to utilize the conductivity of the plate. This arrangement is particularly useful in the absorber for the reason that when only the upper side of the late is used, the pool of liquid assumes di erent concentrations. As ammonia is absorbed in the water the water can take up less ammonia. If a layer of concentrated absorption liquid lies on the top of a pool on an absorber plate it may prevent the absorption of ammonia by liquid lower I down in this pool. By using the under-side of the plate in the manner I have suggested, this disadvantage is obviated in that the full capability of absorbing of the liquid can be utilized.

Other forms of film-holding material may be used and it is even possibleto cut grooves in the under-side of the plate in such a manner that a capillary film is continuously held on the under-side of the plate.

In Fi s. 4 and 5 is shown a modified form of absorier plate wherein the wire mesh projects upwardly within apertures 53 and adjacentthe raised-rims 54;. The wire mesh is and 61. Space ring 57 is relatively thin, for

held in place by a ring 55 and a cross-member 56. Asthe liquid on the upper-side of the plate fiows over the rims 54 it will be readily seen that the liquid flows into the wire mesh 51.

Figs. .6 and 7 show a still further form wherein the Wire mesh 51 is definitely spaced from the under-side of the absorber by means of a spacing member 57 A hole 58 is provided in the wire mesh diametrically opposite a hole 59 through which the liquid flows from one plate to the next lower so that the liquid caught in the wire mesh is carried across the wire mesh to a greater or lesser extent and falls to the next lower plate at a point opposite the place where the wire mesh receives the liquid. This assures a greater utilization of the wire mesh.

In Fig. '8 the arrangement is substantially as in Fig. 7 except that a piece of the wire mesh 60 is cut off and bent downwardly to give a natural path of flow-of liquid from a given wire mesh to the next lower plate. This form has a spacing ring 57 and a second ring 61 for holding the wire mesh in position and separating the plates. The wire mesh is preferably spot-welded between the two rings 57 example one-thirty-second of an inch.

While I have described various modifications ofmy invention, it will be understood that I am not limited to the form above described but that other forms may be used evaporator plates and to evaporator plates without being applied to absorber plates.

' Having thus described my invention, what I claim is:

1. In a refrigerating system comprising interconnected vessels includin a generator, a condenser, an evaporator an an absorber, said evaporator and absorber being interconnected to form a cycle for circulation of an auxiliary agent in the presence of which a cooling agent evaporates and plates within the said cycle of the system for providing gas and liquid contact surface, the combination therewith of wire screening under said plates and adjacent thereto for holding capillary films of liquid on the under-sides of the plates.

'2. In a refrigerating system comprising interconnected vessels including .a generator, a condenser, anevaporator and an absorber, said evaporator and absorber being interconnected to form a cycle for circulation of an auxiliary agent in the presence of which a cooling agent evaporates and plates within the said cycle of the system for providing gas and liquid contact surface, the combination therewith of perforated metal members under said plates and adjacent thereto for'holding capillary films of liquid on the under-sides of the plates.

j 3. In a refrigerating system comprising interconnected vessels including a generator, a condenser, an evaporator and an absorber,

said evaporator and absorber being interconnected to form a cycle for circulation of an auxiliary agent in the presence of which a cooling agent evaporates and plates within the said cycle of the system for providing gas and li uid contact surface, the combination therewith of metallic means for holding liquid on the under-sides of said plates.

4. In a refrigerating system comprising interconnected vessels including a; generator, a condenser, an evaporator and an absorber,

said evaporator and absorber being interconnected to form a cycle for circulation of an auxiliary agent in the presence of which a. cooling agent evaporates and plates within the said cycle of the system for providing gas and liquid contact surface, the combination therewith of wire screening under said plates and attached thereto for holdin capillary films of liquid on the under-sides-of the plates.

5. In a refrigerating system comprising interconnected vessels includin a generator, a condenser, an evaporator an an absorber, said evaporator and absorber being interconnected to form a cycle for circulation of an auxiliary agent in the presence of which a.

cooling agent evaporates and plates within the said cycle of the system for providing gas and liquid contact surface, the combination therewith of wire screening under said plates and adjacent thereto for holding capillary films of liquid on the under-sides of the plates, said wire screening being arranged to contac liquid on the upper sides of said plates.

6. In a refrigerating system comprising in therewith of metallic means for holding liquid on the under-sides of said plates, said metallicmeans being arranged to contact liquid on the-upper sides of said plates.

7. A vessel suitable for use in a refrigerator system comprising a plurality of superposed plates having, parts adapted to permit formation of pools of liquid on said plates and wire screening under said plates and adjacent thereto for holding capillary films of liquid on the under-sides of the plates.-

8. A vessel suitable for use in a refrigerator system comprising a plurality of superv posed plates having partsiadapted to permit formation of pools of liquid on said plates and perforated metal members under said plates and adjacent thereto for holding capillary films of liquid on the under-sides of the plates.

9. A vessel suitable for use in a refrigerator system comprising a plurality of superposed plates having parts adapted to permit formation of pools of liquid on said plates and metallic means for holding liquid on the under-sides of said plates.

10. A vessel suitable for use in a refrigerator system comprising a plurality of superposed plates'having parts adapted to permit formation of pools of liquid on said plates and wire screening under said plates and at tached thereto for holding capillary films of liquid on the under-sides of the plates.

11. A vessel suitable for use in a refrigerator system comprising a plurality of superposed plates having parts adapted to permit formation of pools of liquid on said plates and wire screening under said plates and adjacent thereto for holding capillary films of liquid ,on the under-sides of the plates, said .'wire screening being arranged to contact liquid,

on the upper sides of said plates. p

12. A vessel suitable for use in a refrigerator system comprising a plurality of superposed plates having parts adapted to permit formation of pools of liquid on said plates and metallic means for holding liquid on the under-sides of said plates, said metallic means being arranged to contact liquid on the upper sides of said plates.

13. A plate for use in refrigeratin apparatus comprising wire mesh on one si e for reltaininga capillary film of liquid against the p ate.

4 1 14. In .a refrigerating system comprising interconnected vessels including a generator,

a condenser,'an evaporatcr and an absorber, said evaporator and absorber being interconnected to form a cycle for circulation of an auxiliary agent in the presence of which a cooling agent. evaporates and plates within the said cycle of the system for providing gas and liquid contact surface, said plates having apertures and raised rims surrounding said apertures, the combination therewith of wide screening under said plates and adjacent thereto for holding capillary films of liquid cooling agent evaporates and plates within said evaporator for providing as and liquid contact surface, the combination therewith of wire screening .under said plates and adjacent thereto for holding capillary films of liquid on the under-side's of the plates.

16. In a refrigerating system comprising interconnected vessels including a generator,

a condenser, an evaporator andari absorber, said evaporator and absorber being interconnected to form a cycle for circulation of an auxiliary agent in the presence of which a cooling agent evaporates and plates within said evaporator for providing gas and liquid contact surface, the combination there-, wlth of metallic meansfor holding liquid on the under-sides of said plates 17. In a refrigerating systemcomprising interconnected vessels includin a generator, a condenser, an evaporator an an absorber,

said evaporator 'and absorber being intercom nected to form a cycle. for circulation of an auxiliary agent in the presence of which a coolin agent evaporates and plates within said a sorber for providing gas and liquid contact surface, the combination therewith of wire screening under said plates and adj acent thereto for holding capillary films of liquid on the under-sides of the plates.

18. In a refrigerating system comprising interconnected vessels including a generator, a condenser, an evaporator an an absorber, said evaporator and absorber 'being interconnected to form a cyclefor circulation of an auxiliary agent in the presence of which a coolin agent evaporates and plates within said a sorber for providing gas and liquid contact surface, the combination therewith of metallic means for holding liquid on the a condenser, an evaporator and an absorber,

said evaporator and absorber being interconnected to form a cycle for circulation of an auxiliary agent in the presence of which a cooling agent evaporates, said cycle including means for providing gas and liquid contact and heat conductivity comprising a. metalmember having a drainage surface and Wire screening adjacent said drainage surface for holdlng a capillary film of liquid against said member.

20. Plating for use in refrigeration apparatus having a drainage surface and wire mesh attached to said plating adjacent said drainage surface for retaining a capillary film of liquid against said plating.

21. In a refrigerating system comprising interconnected vessels including a generator, a condenser, an evaporator and an ab sorber, said evaporator and absorber bemg interconnected to form a cycle for circulation of an auxiliary agent in the presence-of which a cooling agent evaporates, said cycle,

including means for provlding gas and liquid contact and heat conductivity comprising a metal member having a drainage surface and a metallic perforated element adjacent said drainage surface for holding a capillary film of liquid against said member.

22. In a refrigerating system comprising interconnected vessels includin a generator,

a condenser, an evaporator an an absorber,"

1 said evaporator and absorber being interconnected to form a cycle for circulation of an auxiliary agent in the presence of which a cooling agent evaporates, said cycle including means for providing gas and liquid contact and heat "conductivity comprising a metal member having a drainage surface and wire screening adjacent to said drainage surface and spot-welded to said member for holding a capillary film of liquid against said member.

In testimony whereof I have aflixed my signature.

B0 KARL GEORGE EHNBOM. 

